<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
.triangle{
    width: 0;
    border-bottom: 35px solid lightgreen;
    border-left: 35px solid transparent;
}
.triangle:after{
    content: '';
    border: 35px solid transparent;
    border-bottom-color: lightgreen;
}
  </style>
</head>
<body>
  <!-- [css] 用CSS绘制一个三角形 -->
  <div class="triangle"></div>
</body>
</html>
<style>

</style>
<script>
